Recently, in magnetic disk devices, a technique of estimating a vibration frequency of a disturbance component applied to a head using an adaptive filter in a servo system that performs head positioning control and filtering the estimated frequency from a head drive signal has been proposed. In the conventional filter processing, however, only one vibration frequency can be handled by a transfer function of the adaptive filter, and there is a possibility that the operation becomes unstable when vibration of a plurality of frequencies is applied.
An object of an embodiment of the present invention is to provide a magnetic disk device capable of eliminating an unstable operation due to vibration frequencies of a plurality of disturbance components in head positioning control, and a head position control method therefor.